Dynamo-electric machine.



W. F. DAWSON.

DYNAMO ELECTRIC MACHINE.

APPLICATION FILED DEC. 19, 1904.

998,677, Patented July 25,1911.

2 SHBETS-SHEET 1.

Witnesses: Inventor:

William F. Dawson,

W 1"; DAWSON. DYNAMO ELECTRIC MACHINE.

APPLICATION FILED DEG.19, 19041 998,677, Patented July 25, 1911.

2 SHEETS-SHEET 2.

Fig.5.

Witnesses. Inventor:

/6 2 William FDawson,

WILLIAQI DAWSON, OISCHENECTADY, NEW YORK, ASSIGNOB TO GENERAL ELECTRIC "comm; A YQQRORATION or NEW YORK.

nrnaalommcriuc momma.

To all whom it may Be it known that I, WiLLIAM F. Dawson,

a citizeii of'the-Unitetl States, residing at Schenectady, county of Schenectady; State of New York, have invented certain new-and useful In1provements'"in Dynamo-Electric Machines, of which the followi'ng is a specififca'tion.

f I My present invention has for one of its objects tl1eproduct'ion"of*a simple but reliable commutator construction particularly adapted for, withstanding the centrifugal forces developed athi'gh speeds. Y i

the combination; in a commutator construction of collector rings for alternating our- 7 rentconnections. a

The various "features" of novelty which .25 which I have illustrated one embodnn'ent of my invention. 5

Of the-drawings, Figure 1 is an. end elevation with parts broken away and in section showing aportion of a dynamo electric machine constructed in accordance with my invention; Fig. 2 is a partialsection taken on'the line 2 2 of'Fig. 1; and Fig. 3 is a perspective view with parts broken away and inv section showing my improved con struction.

Referrin the shaft 0% end of which is journaled in a suitable bearing box 2 supported'by a pillow block 2'. 40 A member'3, the outer surface 4 of which is cylindrical is secured to the shaft 1. In the form of construction illustrated, a sleeve 5, which may also support the armature, not shown, is placed-between the member 3 and the shaft 1. A series of commutator'bars 6, each placed parallel to the axis of the shaft 1, are disposed'about the cylindrical surface of the member 4 in the usual manner, ad- 'acent parts being insulated from each other y strips 7 of insulating material, and from the member 3 by a layer of insulating material -8.; The-bars 6 are secured in position 'by metal clamping rin' s9, 9' and is)" which surround the bars an are insulated from to the drawings, 1 represents Another 'obje'ctof' my present invention is a dynamo electric machme, one

ri ge or Specification of Letters Patent. Patented July 25, 19 11. Application aieanea'e mberia'iood. .Serial no. 2a7,a7o.

them by insulating material 10. Preferably theriugs' 9'- areexpanded by heatbefore placing them about the bars," so that when the rings-cool they will shrink and firmly lock the bars in position on the member 3.

As shown a circumferentially extending tongue or rib "11 is formed on'the inner periphery of each clamping ring. The commutator bars are each formed'with a corresponding notch or depression l2. When the rings are shrunkjnto position the insulating material, which serves toelectrically separate the'hars from the clamping rings by its flexibility, allows the clamping rings and bars to be virtually interlocked. A sufiicient number of clamping rings are placed on the commutatorba'rst-o hold them firmly in sition and-to prevent'their distortion un er the stresses produced by operating conditions. Frequently a pair of rings placed one at: each end of the commutator bars are suflicient to hold the bars in place. 'Un-' number of brushes in engagement with the commutator bars. Suitable connections are made'between the commutator bars and the winding of the armature (not shown in the drawings) in the usual manner.

As is clearly shownlinthe drawings, the

ends of the commutator bars are undercut as indicated at 6. The insulating stri s 7, which are not under-cut, extend beyond the ends of the bars and form a means for firmly holding the projecting end of the insulatingmaterial 8 against the surface 4.

By under-cutting the ends of the commutator' bars as indicated at 6 an ample leakage distance between the ends of the commutator bars and the commutator shell 3 is obtained and the liabilty of breakdown tator bars is materially reduced; In order to prevent the accumulationofdirt in the space between the projecting ends of the insulating strip 7,; such space may be filled with some adhesive'insulating material. In

of the insulation at the end of the commu- 1 form notches in the commutator bars to fit the ridge 4:. This construction 'i's.particularly useful with vertical shaft machines.

When it is desired to make-alternating current connections with the windings of net and comprises twelve portions in para threaded openings formed in the bars. some cases I may widen the ends of the bars.

lel, connections are made from the right hand ring 9 tosix equally distant commutator bars. An equal number of connections is made from the adjacent ring 9' to six commutator bars which are located midway between the commutator bars to which the right hand ring is connected. With this construction, when the machine of which the commutator forms a part is used as a .generator, it will be readily understood that single-phase alternating current can be collected from the rings 9 and 9 in' the usual manner, while at the same time direct current may, if desired, be taken from the commutator bars in the usual manner. a In the construction illustrated, the connections between rings 9 and 9' and the proper commutator bars 6 are made by.

threaded rods 13 which are screwed through suitable openings formed in the rings into In to which connections are made as indicated at 15 in order to get the proper strength of connect-ion. In such cases I shorten the adjacent commutator bars as indicated at 14.

In order to limit the heating of commutators or collector rings I may secure fan blades in juxtaposition to them, as shown for instance in the drawings where fan blades 16 are secured to the ,end of the member 3 by bolts 17 which are tapped into the member. Each fan blade 16 is doubleended and is supported in the middle by the bolts 17, so that the fan bladesextend both outwardly and inwardly from the periphcry of the commutator. It will be readily understood that the revolution of the arma ture shaft will cause these fans to generate air currents. In order that the air currents genera-ted by the fan blade 16 may be forced axially over the surface of the heated contact'conductors, whether commutator bars, collector rings, or both, I employ adc fiector or shield 18 which, in the 'construction shown in Figs. 1 and 2, is secured to the bearing box 2 and to the pillow block 2 by bolts 19. The shield 18 which is'substantially circular in outline is dish shaped and is arranged with its outer edge20 .projecting over the fan blades 16. It will be electrical connections between said ring and readily understood that the shield shaped as shown will deflect the air currents generated by the fan blades axially along the surface of the contact conductors in the direction indicated by the full line arrows shown in Fig. 2. I t

In some cases I prefer to omit the shield 18. \Vhen the shield 18 is omitted the air currents generated by the direct action ofthe fan blades flow radially out from the end of the commutator. The currents directly generated by the fan blades, however, create induced currents which flow in the directions indicated by the dotted line.

arrows inFig. 2 of the drawings. The in-' duced currents serve to cool the surface of the commutator.

While I have hereinbefore described and illustrated the best form of my invention now known to me it will be readily understood by those skilled in the art that changes can be made in the form inwhich my invention is embodied without departing from the spirit of my invention. 1 i

What I. claim as new and desire to secure by Letters Patent of the United States, is:

1. In combination, a support, commutator bars arranged thereon, a ring for securing the bars in fixed relation to the support, an 5 9 one or more of the bars, the ends of the bar or bars to which connections are made being widened to facilitate such connection an adjacent bars being shortened.

2. In combination, a cylindrical support, commutator bars arranged thereon, a ring for securingt-he bars in fixed relation to the support, and electrical connect-ions between sald ring and one or more of said bars, portions of the bars to which connections are made being enlarged to facilitate such connection.

3. In combination, a support, commutator bars arranged thereon, a ring for securing the bars in fixed relation to the su port, and electrical connections between sai ring and one or more of the bars, the end of the bar or bars to which connection is made being widened to facilitate such connection.

4. In combination, a metallic cylindrical support, a cylindrical layer of insulating material surrounding said support, commutator bars arranged about said support, a ring for securing the-bars in fixed relation to said support, and strips of insulating material between'adjacent commutator bars, said strips projecting beyond the ends of said bars and serving to hold the end of the cylindrical insulating material against the support.

5. In combination, a cylindrical support, commutator bars arranged. about said suport and separated therefrom by a layer of insulating material, said layer of insulating material projecting beyond the inner edges the projecting ends ,of the layer of insulating material against the cylindrical support.

'6. In combination, a cylindrical support, a; layer of insulating material surrounding said support, commutator bars, the'ends of which are undercut arranged about said support, a metalring for securing the bars in fixed relation to said support, and insulating material between adjacent commutatombars extending beyond said undercutends to hold said layer of insulatingmaterial against the support.

7. In combination, a cylindrical support,

.a layer of insulating material surrounding said support, commutator bars arranged about sa-idsupport, a ring for securing the bars in fixedrelation to said support, strips of insulating material between adjacent commutator ars, said strips projecting beinsulating material between t .yondthe ends of said bars and serving to hold the end of said layer of insulating material against the support, and insulating material filling the spaces between the projecting ends of said strips.

8. In combination, a cylindrical support, a layer of insulating material surrounding said support, commutator bars arranged about said support, the ends of said bars being undercut, a ring for securing the bars in fixed relation to said support, insulating material between adjacent commutator bars extending beyond said underoutends to hold said layer of insulating material a ainst the support, and insulating material lling the spaces between the projectin ends of said fie commutator bars.

In witness whereof I have hereunto set my hand this 16th day of December, 1904.

WILLIAM F. DAWSON.

Witnesses BENJAMIN B. HULp, HELEN Oman. 

